• on Audio/Video/Photography
  • Published in issue 5/2008 on page 44
About the article

paX: a power amplifier with error correction (2)

The voltage amplifier and input buffer stages

paX: a power amplifier with error correction (2)
Last month we discussed the principle of error correction and developed an error-correction power output stage. In this installment we will use H.ec in a voltage amplification stage and present the complete amplifier.
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Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor Members can exclusively download these files for free as part of their Membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service. Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.


(0.25W metal film)

R1-R4,R6,R8,R17,R18 = 47Ω

R7 = 220Ω

R9,R10,R12,R25,R34 = 4kΩ7

R11 = 249Ω

R13 = 2kΩ74

R16 = 5kΩ23

R19,R20,R30,R31 = 2kΩ15

R21-R24,R60 = 100Ω

R26,R27,R33,R40-R43,R46,R51 = 1kΩ

R28 = 10Ω

R29 = 3kΩ0

R32 = 33Ω

R35,R36 = 619Ω

R37,R38 = 680Ω

R39,R45 = 1MΩ

R44 = 7kΩ5

R47,R48 = 1kΩ8 2W MF

R49,R50 = 10 kΩ

R52-R55 = 0Ω22 5W ceramic

R64 = 1Ω5 2W

R65 = 6(8 2W

RV1, RV2 = 200( multiturn trimmer

R5,R14,R15,R56-R59, R61-R63 = not present



C1,C3,C23 = 150pF polypropylene

C2, C4,C5,C9,C14-C16,C19,C22, C24,C25 = 100nF cer.

C6-C8,C13,C21 = 1µF 63V foil

C10 = 220nF 50V cer.

C11,C12,C17,C18 = 470µF 63V

C26 = 1nF foil



L1 = 5µH (see text)



D1, D2, D5,D6,D10,D11 = zener diode 15V 0.5W

D3,D4,D9,D12,D13,D14 = 1N4148

D7,D8 = 1N4003

Q1,Q2,Q9 = 2SA1208

Q3,Q4,Q10 = 2SC2910

Q5,Q11,Q17,Q18 = BC546B

Q6,Q14,Q19,Q20 = BC556B

Q13,Q16 = STD03N (+ isolation pad & mounting hardware)

Q12,Q15 = STD03P (+ isolation pad & mounting hardware)

U1,U2,U4 = AD844AN

U3 = TL051CP



J9 = header 2 x 1 pin (signal input)

J10 = header 2 x 3 pin (+ flatcable)

4 IC sockets DIL08

PCB, ref. 071085-1
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